It can cause gyno, especially if >150 mg is used.
It's an antiandrogen, so you don't want to take it orally bacause it can negatively affect your gains.
J Steroid Biochem. 1989 Jan;32(1B):223-7. Related Articles, Links
Antialdosterones: incidence and prevention of sexual side effects.
de Gasparo M, Whitebread SE, Preiswerk G, Jeunemaitre X, Corvol P, Menard J.
Research Department, CIBA-GEIGY Limited, Basle, Switzerland.
The use of spironolactone in the treatment of hypertension has been limited by the occurrence of sexual side effects, mainly menstrual disturbances in women and gynaecomastia in men. In order to minimize this limitation on the use of an effective potassium-sparing antihypertensive agent, two strategies can be proposed: (1) A decrease in the daily dose of spironolactone. In 182 patients with essential hypertension treated with spironolactone alone for a mean follow-up period of 23 months, daily doses of 75-100 mg were as effective on blood pressure as doses of 150-300 mg. In contrast, the development of gynaecomastia--91 cases among 699 men--was dose-related in 6.9% (50 mg/day) to 52.2% (150 mg or more/day) of the cases. (2).. An improvement in the receptor-binding specificity of spironolactone. Three 9 alpha, 11 alpha-epoxy derivatives have been characterized in vitro in rats and in rabbits. They exhibited a 3- to 10-fold decrease of the antiandrogenic and progestagenic effect, compared with spironolactone. In humans, one of these derivatives counteracted the fall in urinary Na/K ratio induced by 9 alpha-fluorohydrocortisone at a 25 mg dose.
-----------------------------------
Andrologia. 1986 Jan-Feb;18(1):104-7. Related Articles, Links
[Drug-induced gynecomastia]
[Article in German]
Schirren U, Hinz B, Schirren C.
Concerning four own observations by men in the age of 41-69 years it has been reported about the drug-induced gynecomastia. It can be demonstrated that the spironolactone induced gynecomastia disappeared after stopping this drug. The knowledge of such side effects is the condition for a pre-information of the patient at the beginning of therapy. The mode of action of spironolactone is discussed. It is referred about the important role of the disturbance of the relation androgen: estrogens under spironolactone as well as the peripheral antiandrogen effect of this substance.
----------------------------------
BMJ. 1994 Feb 19;308(6927):503-6. Related Articles, Links
Erratum in:
BMJ 1994 Mar 26;308(6932):819.
Risk of gynaecomastia associated with cimetidine, omeprazole, and other antiulcer drugs.
Garcia Rodriguez LA, Jick H.
Boston Collaborative Drug Surveillance Program, Boston University Medical Center, Lexington, MA 02173-5207.
OBJECTIVE--To study the risk of gynaecomastia associated with cimetidine, misoprostol, omeprazole and ranitidine. DESIGN--Open cohort study with nested case-control analysis. SETTING--General practices in United Kingdom that had computerised offices, 1989-92. SUBJECTS--81,535 men aged 25-84 years who received at least one prescription for cimetidine, misoprostol, omeprazole, or ranitidine during the study period. MAIN OUTCOME MEASURES--New occurrences of idiopathic gynaecomastia diagnosed by general practitioner. RESULTS--The relative risk of gynaecomastia for current users of cimetidine compared with non-users was 7.2 (95% confidence interval 4.5 to 11.3). Relative risks for misoprostol, omeprazole, and ranitidine were 2.0 (0.1 to 10.7), 0.6 (0.1 to 3.3), and 1.5 (0.8 to 2.6), respectively. Current users of cimetidine on a daily dose > or = 1000 mg had more than 40 times the risk of developing gynaecomastia than non-users. The period of highest risk was seven to 12 months after starting cimetidine treatment. Spironolactone (relative risk 9.3 (3.3 to 26.1)) and verapamil (9.7 (2.6 to 36.0)) were associated with a relative risk of gynaecomastia comparable to one for cimetidine. CONCLUSIONS--Use of cimetidine, but not the three other antiulcer drugs, is associated with a substantially greater risk of gynaecomastia in men. A strong dose-response relation was present among cimetidine users.